This invention relates to an arrangement for controlling the quantity of fuel injected during each injection cycle of an internal combustion engine. It is desired that the quantity of fuel injected per cycle be the optimum based upon the operating parameters of the engine. In the systems here under consideration, the quantity of fuel is a function of the injection time during which the injection means of the internal combustion engiene are open.
The exhaust of an internal combustion engine which has an injection arrangement instead of a carburetor can be substantially free of products of incomplete combustion if the amount of fuel injected during each cycle corresponds to the current operating conditions of the engine.
Electronically controlled systems for controlling the amount of fuel injected during each operation cycle comprise electromagnetically operated injectors to which fuel is furnished under constant pressure, so that the quantity of fuel depends directly upon the time that the injectors are open.
In conventional injection systems, the main timing element is a monostable multivibrator whose unstable condition controls the injection time, or, the time the injectors are open. The time which the monostable multivibrator remains in the unstable state, is determined by the operating parameters of the engine. However, changes in the electrical parameters of the components constituting the monostable multivibrator circuit can also affect time in which the monostable multivibrator remains in the unstable state, so that errors in the injection time are introduced due to aging of components, replacement of one component by another with slightly different electrical characteristics, etc.